fun with time’s arrow

I had an epiphany this week. I’m sure it’s not an original idea, but it’s the first time it dawned on me. We all have an intuitive grasp that the future can play out in multiple ways. We can imagine that, staring from an arbitrary point in time, say April 25, 12:00 pm ET–let’s call that the origin–time will unfold in a certain way, dependent on an unfathomable number of contingencies. It makes sense that if we return to the origin and run time forward again, time will play out differently, owing to the randomness of the contingencies.

Here’s the epiphany: what if we return to the origin and play time backwards? The intuitive instinct which I suspect most people have is that time would play back the same way always, because, after all, it already happened that way. But in fact, wouldn’t time play out differently every time we start at the origin and go backward from there? Wouldn’t the contingencies and randomness come into play? Wouldn’t there be an infinite number of possible pasts, just as there are an infinite number of futures?